Edible Seaweed Research Articles

Hydrolysis and cross-flow ultrafiltration as an alternative process to isolate fucoidans from edible seaweed Nizamuddinia zarnardinii with enhanced immunostimulatory efficacy

In the present investigation, fucoidan isolated from Nizamuddinia zanardinii was hydrolysed using 0.01 N HCl at boiling temperature for 10, 20, 40 and 60 min. Native and hydrolysed fucoidans contained a close chemical compositions, most importantly constituted of sulfates and uronic acids as well as fucose, galactose and mannose. Hydrolysis and cross-flow ultrafiltration produced fucoidan hydrolysates having different weight average molecular weights. The FH20 fucoidan was the most potent polysaccharide hydrolysate to stimulate NO-release from RAW264.7 macrophage cells. After cross-flow ultrafiltration of FH20, 100 < kDa fucoidan, polysaccharide with high branching degree consisting mainly of (1 → 2)-Fucp, (1 → 2,3)-Fucp, (1 → 3)-Galp, (1 → 2,3)-Galp, (1 → 2)-Manp and (1 → 3)-Manp residues, exerted the highest stimulation effect on RAW264.7 macrophage cells, secreting considerable NO, TNF-α, IL-1β, IL-6 and IL-12 proinflammatory mediators. Also, 100 < kDa fucoidan activated NK-92 cells to release TNF-α, INF-γ, granzyme-B, perforin, NKG2D and FasL. Both RAW264.7 and NK-92 cells were activated through NF-κB and MAPKs signalling pathways and the degree of stimulation capacity in fucoidan from N. zanardinii was in close correlation with the molecular weight.

Action and cooperation in alginate degradation by three enzymes from the human gut bacterium Bacteroides eggerthii DSM 20697

Alginate is a polysaccharide consumed by humans in edible seaweed and different foods where it is applied as a texturizing hydrocolloid or in encapsulations of drugs and probiotics. While gut bacteria are found to utilize and ferment alginate to health beneficial short chain fatty acids, knowledge on details of the molecular reactions is sparse. Alginates are composed of mannuronic acid (M) and its C-5 epimer guluronic acid (G). An alginate related polysaccharide utilization locus (PUL) has been identified in the gut bacterium Bacteroides eggerthii DSM 20697. The PUL encodes two polysaccharide lyases (PLs) from the PL6 (BePL6) and PL17 (BePL17) families as well as a KdgF-like metalloprotein (BeKdgF) known to catalyze ring-opening of 4,5-unsaturated monouronates yielding 4-deoxy-l-erythro-5-hexoseulose uronate (DEH). B. eggerthii DSM 20697 does not grow on alginate, but readily proliferates with a lag phase of a few hours in the presence of an endo-acting alginate lyase A1-I from the marine bacterium Sphingomonas sp. A1. The B. eggerthii lyases are both exo-acting and while BePL6 is strictly G-block specific, BePL17 prefers M-blocks. BeKdgF retained 10−27% activity in the presence of 0.1−1 mM EDTA. X-ray crystallography was used to investigate the three-dimensional structure of BeKdgF, based on which a catalytic mechanism was proposed to involve Asp102, acting as acid/base having pKa of 5.9 as determined by NMR pH titration. BePL6 and BePL17 cooperate in alginate degradation with BeKdgF linearizing produced 4,5-unsaturated monouronates. Their efficiency of alginate degradation was much enhanced by addition of the A1-I alginate lyase.

Metabolomic analysis of umami taste variation in Pyropia haitanensis throughout the harvest cycle

Porphyra sensu lato, a highly valuable edible seaweed renowned for its distinctive umami taste, undergoes significant taste variations during the harvest cycle, affecting product quality and pricing. In this study, umami-related metabolites in Pyropia haitanensis were investigated at different harvesting times using GC–MS metabolomic, targeted LC-MS analysis, and an electronic tongue taste evaluation. High concentrations of compounds, including glutamic acid, aspartic acid, and inosine 5′-monophosphate, were identified as the main contributors to the overall umami profile. The concentrations of the compounds and umami-enhancing substances, such as sugars, were negatively correlated as the harvesting period extended. The early harvested P. haitanensis exhibited a superior umami taste, which gradually decreased with subsequent harvest time. Proline, a known cold-resistance metabolite, accumulated as the seawater temperature decreased and the harvest period progressed. These findings provide insights into the optimal cultivation and harvesting practices for maintaining umami quality in P. haitanensis products.

A critical review of the edible seaweed Palmaria palmata (L.) Weber & Mohr and its bioactive compounds in the “omics” era

The red alga Palmaria palmata (“dulse”; Palmariaceae, Rhodophyta) has been used as food since the fifth century, especially in the North Atlantic region. Dulse is a good alternative to cereals due to its high nutritional profile. A critical review based on scientific and grey literature of dulse bioactive compounds and their activity identified key knowledge gaps. The review synthesis emphasizes the importance of species delimitation, microbial community characterization and multi-omics in the research of P. palmata. Recent advances and uncertainty in delimitating P. palmata are introduced in a phylogenetic context, and recommendations are given for future phytochemical studies. We refer to the concept of “seaweed holobiont” as the functional entity encompassing the seaweed and its associated microbiota, and call for action to characterize the microbial communities, since their interactions with the environment and seaweeds are important in seaweed well-being and postharvest quality changes (e.g. microbial spoilage and degradation of algal matrices). Finally, we discuss the status and trends of using multi-omics to address important research questions of P. palmata, and to help us understand the source, biosynthesis and function of its bioactive compounds.

Gim (Porphyra yezoensis) Flakes for Decreased Sodium Content of Fried Surimi Fish Cake

ABSTRACT The study was to investigate the influence of the addition of sea vegetable (gim) flakes on physicochemical, nutritional, and antioxidative properties and stability over storage of salt-reduced fried fish cake. The addition of gim flakes at 1%, 2%, and 3% (w/w) in fried fish cake reduced the salt content by 13%, 15%, and 18%, respectively. Fried fish cakes prepared with gim flakes demonstrated lower fat and sodium content and higher protein, phenolic content, and antioxidative properties. The results of these studies demonstrated that the beneficial value and overall quality of fried fish cake can be improved through the addition of gim.

Immunomodulatory potential of sulfated xylated rhamnoglycan from an edible green seaweed Ulva lactuca: Regulation of cytokine expression in CALU-1 cells and prospects for therapeutic applications

Green seaweeds, particularly Ulva lactuca, commonly known as sea-lettuce, from the Ulvaceae class, constitute a significant proportion of the global edible seaweed population and serve as a rich storehouse of pharmacologically active compounds, including polysaccharides. In this study, a sulfated (1 → 4) linked xylated rhamnoglycan, (ULP-2), was extracted from Ulva lactuca. ULP-2 displayed significant immunomodulatory properties by modulating the expression of inflammatory cytokines in lipopolysaccharide (LPS)-induced CALU-1 non-small-cell lung cancer (NSCLC) cells. Treatment with ULP-2 at a concentration of 125 μg/mL resulted in a notable downregulation (63%, p < 0.05) of interferon (IFN)-γ gene expression compared to LPS-treated cells. Furthermore, the overexpression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β was significantly attenuated (p < 0.05) with ULP-2 treatment (125 μg/mL), showing substantial downregulation to 0.82% and 1.81%, respectively, compared to LPS-induced cells (29.28% and 94.89%, respectively). Additionally, a noteworthy 1.3-fold reduction in IL-33 expression was observed following the administration of ULP-2 at 125 μg/mL. An upregulation of IFN-α expression, was evident in LPS-induced CALU-1 cells following treatment with ULP-2 within the concentration range of 31.25–125 μg/mL. The structure-activity study reinforced the significance of the presence of polyanionic sulfate and the (1 → 4) linkage in ULP-2 for binding to their respective receptors, influencing the orientation and spatial arrangement of the molecule, and subsequently triggering intracellular signaling pathways linked to the activation of innate immunity. Consequently, this study highlights ULP-2 as a promising natural compound derived from edible seaweed with potential applications in the treatment of inflammatory disorders and immune enhancement.

Bio-accessibility and bio-availability evaluation of each arsenic species existing in various edible seaweeds in vitro and in vivo for arsenic risk assessment

Seaweeds consumption is one of main internal exposure sources of arsenic for human. However, the absence of representative bio-availabilities of arsenic species makes the accurate assessment of arsenic health risk originating from seaweeds consumption impossible. Herein, the arsenic species in various seaweeds collected from Fujian of China were investigated, and the bio-accessibilities/bio-availabilities of arsenic species existing in seaweeds were evaluated in vitro and in vivo. Results revealed that in vitro bio-availabilities of arsenic species presenting in seaweeds, which obtained with Caco-2 cells, were lower than those of pure arsenic standards, and varied with order of inorganic arsenic (iAs) > dimethylarsinic acid (DMA) ≈ arsenobetaine (AsB) > arsenosugars. During gastrointestinal digestion of mice, As5+ was partly methylated into monomethylarsonic acid (MMA) and DMA, which makes the in vivo bioavailability of iAs (⁓31.8 %) obtained with mouse metabolic experiment is much higher than its in vitro bio-availability (⁓10.3 %). The in vivo bio-availabilities of DMA and total arsenic (tAs) are similar to their in vitro bio-availabilities. As the dominant arsenic species in most seaweeds, arsenosugars have an ⁓0.0 % of in vivo bioavailability and only a ⁓3.7 % of in vitro bioavailability. The simulated calculation of target hazard quotient (THQ) and target cancer risk (TR) revealed that the arsenic risk originating from seaweeds was greatly degraded by taking into consideration of arsenic species and bio-availabilities, and all seaweeds collected from Fujian are safety for consumption. The simulated calculation also revealed that arsenic risk of seaweeds can be also more accurately assessed based on tAs together with bioavailability, which provides a simple but accurate and protective method for the risk assessment of arsenic originating from seaweeds. Our work provides the possible representative bio-availabilities of arsenic species presenting in seaweeds for accurately assessing arsenic risk of seaweeds, and novel insights into the bio-availabilities of arsenic in animal.

A novel seaweed-based biodegradable and active food film to reduce freezer burn in frozen salmon

The imperative to replace conventional plastic food packaging has led to the development of edible and biodegradable alternatives. This study has formulated an effective packaging solution for the preservation of frozen salmon. Alginate films were prepared by integrating ethanolic extracts from two edible seaweeds, Sargassum muticum and Grateloupia turuturu. The optical and mechanical properties of the films, as well as their effectiveness in preserving frozen salmon over a 6-month period at −18 °C, were assessed and compared to other alginate and synthetic plastic films. The quality parameters of the final product were also assessed. Films incorporating Grateloupia extract exhibited a 34% reduction in thickness and 51% lower moisture content when compared to alginate. Meanwhile, those containing Sargassum extract demonstrated improved water resistance, with a 11% decrease in solubility. The seaweed-incorporated films demonstrated gradual biodegradation over time. Samples packaged with these films displayed a substantial decrease in colour changes, ranging from 58% to 64%, compared to commercial plastic film packaging. This enhanced protection against freezer burn is likely due to the presence of lipid-derivate compounds in the Grateloupia extract. The findings of this study suggest the potential use of alginate-based films incorporated with Grateloupia and Sargassum extracts as edible and biodegradable packaging for frozen fish, offering a sustainable and improved alternative to synthetic plastic films.

Exposure to iodine, essential and non-essential trace element through seaweed consumption in humans

Seaweed consumption has gained popularity due to its nutritional value and potential health benefits. However, concerns regarding the bioaccumulation of several trace elements highlight the need for comprehensive studies on exposure associated with seaweed consumption. To address this gap in knowledge, we carried out a feeding intervention study of three common edible seaweeds (Nori, Kombu, and Wakame) in 11 volunteers, aiming to elucidate the extent of both beneficial and harmful trace element exposure through seaweed consumption in humans. Concentrations of total arsenic, cobalt, copper, cadmium, iodine, molybdenum, selenium, and zinc were measured in urine samples before and following seaweed consumption. Elements concentrations were also measured in the seaweeds provided for the study. Descriptive analysis for each element were conducted and we used quantile g-computation approach to assess the association between the 8-element mixture and seaweed consumption. Differences in urine element concentrations and seaweed consumption were analyzed using generalized estimating equations (GEE). Urinary concentrations of iodine and total arsenic increased after seaweed consumption. When we analyze the 8-element mixture, the largest weight was observed for iodine after Kombu consumption while for total arsenic was observed after Wakame consumption. Similar results were observed when we compared the mean differences between the elements before and after seaweed consumption through the GEE. Seaweed consumption relates with increased urinary iodine and total arsenic concentrations, particularly after Kombu and Wakame consumption.

High-Voltage Pulsed Electric Fields and pH Shift Process for Protein and Solute Release from Gracilaria sp., Red Edible Seaweed

AbstractThis study proposes a process based on the application of high-voltage pulsed electric field (PEF) in combination with pH shift for protein and solute release from fresh edible seaweed from Gracilaria sp.. The PEF was administered using a custom-made generator within and electroporation cell with sliding electrodes. The applied PEF parameters comprised 1000 V applied voltage, 50 µs pulse duration, 200 pulses delivered at 3 Hz frequency, and an inter-electrode gap ranging from 3.9 to 4.4 mm. The pH shift extraction was performed through a combination of fractions extracted sequentially at pH-shift steps spanning the pH range of 1 to 12. Both PEF and pH played pivotal roles in the fractionation of Gracilaria sp., enhancing protein release compared to water extraction, PEF pre-treatment, or pH shift alone. The combination of PEF and sequential pH washes (pH 1 to 12) resulted in a total solute release of 9.61 ± 0.04% and protein release of 28.02 ± 0.2% with essential amino acid (EAA) content of 63.6 ± 5.3%, and branched amino acids (BCAA) content of 3.47 ± 0.06%. It is noteworthy that PEF significantly increased the EAA and BCAA content of the protein extracts, irrespective of pH shifts. These findings underscore the promising potential of PEF pre-treatment in extracting proteins from edible seaweeds.

Effects of dietary seaweed on obesity-related metabolic status: a systematic review and meta-analysis of randomized controlled trials.

Seaweed is a promising source of anti-obesity agents, including polysaccharides, proteins, polyphenols, carotenoids, and n-3 long-chain polyunsaturated fatty acids. The anti-obesity effects of such compounds may be due to several mechanisms, including inhibition of lipid absorption and metabolism, effect on satiety, and inhibition of adipocyte differentiation. The aim of this study was to assess the evidence from human randomized controlled trials for the effects of seaweed on body-weight status as well as lipid and nonlipid parameters in adults with overweight and obesity. Four databases-Medline, Scopus, Web of Science, and Cochrane Library-were searched from December 2022 to June 2023 using the following key words: Seaweed OR fucoxanthin OR alginates OR fucoidans OR phlorotannin's OR macroalgae OR marine algae AND obesity OR overweight OR BMI OR body mass index. Eleven interventional studies (10 parallel and 1 crossover) were extracted. Meta-analysis showed a significant effect, favoring the intervention group for BMI (body mass index) (standardized mean difference [SMD]: -0.40; 95% CI: -0.65 to -0.16 kg/m2; P = 0.0013) and percentage of fat mass (SMD: -1.48; 95% CI: -2.66% to -0.30%, P = 0.0138). The results were seen when refined or extracted brown seaweed (BMI) or only refined brown seaweed (% fat mass) were administered to participants for at least 8 weeks. Moreover, a significant overall effect of seaweed supplementation on total cholesterol (SMD: -7.72; 95% CI: -12.49 to -2.95 mg/dL; P = 0.0015) and low-density-lipoprotein cholesterol (SMD: -7.33; 95% CI: -11.64 to -3.02 mg/dL; P < 0.001) was noted. Any significant effects of seaweed on glucose metabolism were not shown. Edible seaweed supplementation shows potential for managing obesity and disorders of the blood lipid profile when administered to participants for at least 8 weeks. PROSPERO registration no. CRD42022378484 (www.crd.york.ac.uk/PROSPERO).

Assessment of Anti-Prostate Cancer Activity among Four Seaweeds, with Focus on Caulerpa lentillifera J.Agardh.

In response to a global shift towards health-conscious and environmentally sustainable food choices, seaweed has emerged as a focus for researchers due to its large-scale cultivation potential and the development of bioactive substances. This research explores the potential anticancer properties of seaweed extracts, focusing on analyzing the impact of four common edible seaweeds in Taiwan on prostate cancer (PCa) cells' activity. The study used bioassay-guided fractionation to extract Cl80 from various seaweeds with androgen receptor (AR)-inhibitory activity. Cl80 demonstrated effective suppression of 5α-dihydrotestosterone (DHT)-induced AR activity in 103E cells and attenuated the growth and prostate-specific antigen (PSA) protein expression in LNCaP and 22Rv1 cells. Additionally, Cl80 exhibited differential effects on various PCa cell lines. Concentrations above 5 μg/mL significantly inhibited LNCaP cell proliferation, while 22Rv1 cells were more resistant to Cl80. PC-3 cell proliferation was inhibited at 5 μg/mL but not completely at 50 μg/mL. A clonogenic assay showed that at a concentration of 0.5 μg/mL, the colony formation in LNCaP and PC-3 cells was significantly reduced, with a dose-dependent effect. Cl80 induced apoptosis in all PCa cell types, especially in LNCaP cells, with increased apoptotic cells observed at higher concentrations. Cl80 also decreased the mitochondrial membrane potential (ΔΨm) in a dose-dependent manner in all PCa cell lines. Furthermore, Cl80 suppressed the migration ability of PCa cells, with significant reductions observed in LNCaP, 22Rv1, and PC-3 cells at various concentrations. These compelling findings highlight the promising therapeutic potential of C. lentillifera J.Agardh and its isolated compound Cl80 in the treatment of PCa.

Purified Pyropia yezoensis Pigment Extract-Based Tandem Dye Synthesis.

Red phycoerythrin (R-PE) is a highly valuable protein found in an edible seaweed, Pyropia yezoensis. It is used extensively in biotechnological applications due to its strong fluorescence and stability in diverse environments. However, the current methods for extracting and purifying R-PE are costly and unsustainable. The aim of the present study was to enhance the financial viability of the process by improving the extraction and purification of R-PE from dried P. yezoensis and to further enhance R-PE value by incorporating it into a tandem dye for molecular biology applications. A combination of ultrafiltration, ion exchange chromatography, and gel filtration yielded concentrated (1 mg·mL-1) R-PE at 99% purity. Using purified PE and Cyanine5 (Cy5), an organic tandem dye, phycoerythrin-Cy5 (PE-Cy5), was subsequently established. In comparison to a commercially available tandem dye, PE-Cy5 exhibited 202.3% stronger fluorescence, rendering it suitable for imaging and analyzes that require high sensitivity, enhanced signal-to-noise ratio, broad dynamic range, or shorter exposure times to minimize potential damage to samples. The techno-economic analysis confirmed the financial feasibility of the innovative technique for the extraction and purification of R-PE and PE-Cy5 production.

Establishment of Effective Callus Induction in the Economically Important Brown Seaweed Ecklonia cava

The edible brown seaweed, Ecklonia cava, is highly valued for its bioactive compounds, and is widely used in food supplements and functional foods. The increasing demand for this seaweed in the food industry emphasizes the necessity for sustainable cultivation practices. This study focused on inducing callus in the meristem and stipe of E. cava using different culture media: Provasoli’s enriched seawater medium (PESI), enriched artificial seawater medium (ESAW), artificial enriched seawater medium (ASP2), or Von Stosch’s enriched seawater medium (VS). Various abiotic stress factors (photoperiod, agar concentration, and temperature), growth regulators, carbon sources, polyamines, and plasma treatments were explored for their impact on callus induction. Both stipe and meristem explants developed callus within three to six weeks across all media except ASP2. Callus development was favored at temperatures between 8 to 13 °C and in the absence of light. Stipe explants showed a higher callus induction rate (up to 65.59 ± 6.24%) compared to meristem (up to 57.53 ± 8.32%). Meristem explants showed optimal callus induction in PESI medium with a low concentration of indole-3-acetic acid (IAA; 40.93 ± 8.65%). However, higher concentrations of IAA and 1-naphthaleneacetic acid (NAA) reduced meristem callus induction. Stipe showed high induced-callus (up to 50.37 ± 5.17%) in PESI medium with low concentrations of IAA, NAA, and 6-benzylaminopurine (BAP). Both stipe and meristem explants induced largest callus at 2% sucrose, but higher carbon source concentrations reduced callus induction. Spermine (Spm) at 1 µM resulted in high induced calluses; however, increasing Spm concentrations decreased callus induction. This tissue culture technique not only supports mass cultivation of E. cava, but also holds potential for extending to other seaweed species, contributing to the sustainability of seaweed stocks for the food industry.

Removal of Nanoplastics from Copollutant Systems Using Seaweed Cellulose Nanofibers.

Nanoplastic pollution poses a significant global concern for public health due to the potential toxicity it induces in the human body through food and water intake. Consequently, the urgent task of removing nanoplastics, especially from water resources, is paramount for enhancing food safety, and developing eco-friendly materials capable of efficiently removing nanoplastics is crucial. In this context, we propose the use of biodegradable anionic seaweed cellulose nanofibers (TEMPO-mediated seaweed cellulose nanofibers, TCNFs) and cationic seaweed cellulose nanofibers (quaternized seaweed cellulose nanofibers, QCNFs) for nanoplastic removal in both single- and copollutant systems. In our experiments under simulated practical conditions, we revealed that TCNFs and QCNFs achieved an average removal efficiency of 98.71% against nanoplastic particles. Moreover, TCNFs and QCNFs exhibited higher adsorption capacities compared to those of existing materials, potentially offering a cost-effective advantage. Toxicity assessments conducted with mammalian cells further confirmed the biosafety of TCNFs and QCNFs. This study contributes to the scientific and theoretical understanding of using edible seaweed as well as offers promising solutions for food safety control in an efficient, cost-effective, and eco-friendly manner.

Common Nutritional Shortcomings in Vegetarians and Vegans

The popularity of vegetarian and vegan diets is growing due to increased awareness of the environmental and health benefits of such diets. However, despite the consumption of meatless diets being associated with decreased risk of chronic diseases and mortality, followers of these diets are prone to certain nutritional inadequacies, which could limit health benefits. The main nutrients of concern are vitamin B12, vitamin D, iodine, selenium, calcium, and iron. It is essential for all those following vegetarian and vegan diets to implement vitamin B12 supplementation. To prevent vitamin B12 deficiency, adults should take one oral dose of 50–100 μg cyanocobalamin daily or 2000 μg weekly divided into two oral cyanocobalamin doses. Iodine supplementation is essential for pregnant and breastfeeding women and is recommended for vegetarians and vegans who are unable to access sea vegetables or iodine-fortified foods. The recommended dose of iodine supplement for adults is 150 μg daily. Selenium supplementation should be reserved for individuals with clinical evidence of deficiency due to concerns of adverse effects on lipid profiles and type 2 diabetes risk. It is recommended that vegetarian and vegan adults should supplement 4000 International Units (IU)/d of oral vitamin D to prevent deficiency as sunlight exposure is unreliable due to a range of lifestyle and environmental factors. This recommendation also applies to omnivores. As a precaution, those wishing to transition to a more plant-based diet should consider how they will substitute the nutrition they currently obtain from animal-based foods with plant-based sources or appropriate supplementation.

Proximate Composition and Heavy Metal Content of Edible Seaweed from Kappaphycus alvarezii and Caulerpa cf. macrodisca ecad corynephora

Edible seaweeds, such as Kappaphycus and Caulerpa genera, have been popularly consumed for centuries by the local people in the Tawi-Tawi, Philippines. This study examined the proximate composition and heavy metal contents of two edible seaweeds, namely Kappaphycus alvarezii (KA) (Rhodophyta) and Caulerpa cf. macrodisca ecad corynephora (CMC) (Chlorophyta), which are readily available in the public market of Bongao, Tawi-Tawi, Philippines. The results revealed significant differences in their proximate compositions. The moisture content was remarkably higher in KA (16.96±0.02 g.100-1g) than that of CMC (10.49±0.08 g.100-1g). CMC contained significantly more crude protein (7.14±0.80 g.100-1g) than KA (2.73±0.40 g.100-1g). The carbohydrate content of KA (44.82±0.34 g.100-1g) was significantly higher than that of CMC (38.09±0.71 g.100-1g). The ash content was notably greater in CMC (44.00±0.66 g.100-1g) than in KA (34.91±0.39 g.100-1g). The total fat content was substantially higher (p≤0.05) in KA (0.60±0.30 g.100-1g) than in CMC (0.28±0.01 g.100-1g). The heavy metal contents (mg.kg-1) followed the order of K &amp;gt; Zn &amp;gt; Fe &amp;gt; Pb &amp;gt; Cu &amp;gt; Mn &amp;gt; Cd for KA and Zn &amp;gt; Mn &amp;gt; Pb &amp;gt; K &amp;gt; Fe &amp;gt; Cu &amp;gt; Cd for CMC. Fe, K, Cu, and Cd were significantly higher in KA than in CMC, while Zn, Mn, and Pb were remarkably higher in CMC than in KA. However, all these heavy metals were found to be within safe limits of WHO, the US (EPA and FDA), and EMA. These findings underscore the importance of considering these factors in seaweed consumption, affirming their enduring significance in human diets.

Characterization of flavor substances in cooking and seasoned cooking brown seaweeds by GC-IMS and E-nose

The flavor of algae was one of the key factors for consumer acceptance. The objective of this study was to investigate the characteristic volatile compounds in cooking and seasoned cooking edible brown seaweeds (Undaria pinnatifida and Laminaria japonica). The gas chromatography-ion mobility spectrometry (GC-IMS) and electronic nose (E-nose) analysis showed that baking resulted in significant difference in flavor of brown seaweeds. However, the overall effect of cooking was not as significant as that of the seasoning solution treatment. Additionally, brown seaweeds treated with the seasoning solution were more acceptable. Undaria pinnatifida was found to contain 72 volatile flavor compounds, while Laminaria japonica had a total of 70. This study proved the applicability of GC-IMS combined with E-nose technology to detect the changes of volatile components of brown seaweeds after processing, providing beneficial knowledge and basic theory for the deep processing of brown seaweeds.

Variation in heavy metals concentrations among seaweed species from Mkwiro seaweed farm, Kwale County, Kenya

This study, conducted at the Mkwiro seaweed farm in Kwale County, Kenya, aimed to assess the concentrations of heavy metals (Cd and Pb) and essential elements (Na, Fe, Ca, and K) in selected edible seaweed species. The study used a cross-sectional, descriptive research design and probability sampling method to collect data. Seaweed samples of three selected species, Cottonii (Kappaphycus alvarezii), Sea lettuce (Ulva lactuca), and Bubble-green seaweed (Boergesenia forbesii) were collected in quadrants and subjected to chemical analysis. Statistical analyses were conducted using R Studio version 4.3.2, with a significance level set at α=0.05. The Kruskal-Wallis test revealed significant differences in lead concentrations among seaweed types (χ² (2) = 7.01, p = 0.03). Cadmium concentrations did not show significant differences (χ² (2) = 3.88, p = 0.14). For calcium concentrations, ANOVA indicated no significant effect of seaweed type (F (2,33) = 0.6381, p = 0.5347). Iron concentrations differed significantly among seaweed types (χ² (2) = 23.35, p = 0.00000849), with B. forbesii having the highest median concentration. Potassium and sodium concentrations did not significantly vary among seaweed types (p &gt; 0.05). The study uncovers elevated cadmium levels in seaweed, indicating potential contamination risks. However, concentrations of essential elements were lower. To address these findings, it is recommended to initiate regular monitoring and pollution control measures in seaweed farms. Additionally, diversifying cultivation with low-metal species can enhance product safety and quality.

The exposure routes of micro- and nanoplastics and their potential toxic effects on human health

This article discusses the classification of micro- and nanoplastics (MNP), the routes of their exposure and the effects of MNP on the reproductive, respiratory, digestive and immune systems based on in vitro and in vivo studies, as well as available epidemiological data. The MNP can enter our body through inhalation, food or skin. The presence of microplastics (MP) in tap, bottled and deep sea water, as well as in sea salt, fruit and vegetables has been demonstrated. Due to their small size, MNP can be absorbed and easily distributed through the blood and lymphatic vessel system to tissues and organs. Recent studies have provided evidence of the accumulation of MNP in human lungs and even in the placenta. The accumulation of MNP in the body may have long-term effects and lead to health problems in humans, such as bronchitis, development of asthma, pulmonary fibrosis, inflammation and cancer. The information included in the article gives partial insight into how MNP may affect the human body. However, to fully assess the toxicity of MNP, comprehensive research is necessary, including standardization of MNP detection techniques and determination of the MNP content in food and water. It is also advisable to assess toxicokinetic parameters, as well as to determine the daily dose of exposure and interaction of MNP with various cells. Insufficient data on direct exposure to MNP in the work environment, as well as in other public places, constitutes a factor hindering the establishment of appropriate legal standards. In 2024, work on establishing the first act of EU law enabling the monitoring of MP in drinking water should be completed, which raises great hopes that in the future limit values for MNP in water and food and in workplaces will also be established. Med Pr Work Health Saf. 2024;75(1):81-96.